The present invention relates to an electric oil pump and a hydraulic pressure supply device that are arranged in, for example, a transmission of a vehicle.
Japanese Laid-Open Patent Publication No. 2011-94553 describes an example of an electric oil pump that includes a motor, a pump rotor driven and rotated by the motor, and a housing accommodating the motor and the pump rotor. The housing is partially fitted into a pump receptacle of a vehicle transmission so that the housing closes the pump receptacle. The housing includes an inlet and an outlet through which oil is drawn in and discharged when the pump rotor rotates. As the pump rotor rotates, oil is drawn into the oil pump through the inlet from an oil inflow passage in the pump receptacle. Further, oil is discharged from the oil pump through the outlet and into an oil outflow passage in the pump receptacle.
In such an electric oil motor, the motor, especially, a stator of the motor is easily heated. When heat is transmitted from the stator to the pump rotor, the pumping properties may be affected. Thus, it is desirable that heat radiation capacity of the electric oil pump be increased.